OK, for arguments sake, we ban all guns everywhere. Every single gun is now gone.

How does that prevent a student from killing another?

Some people, not everyone, but a significant number of people feel powerful with a firearm in their hand. They like that feeling of power. A tactical knife or something like that can give a similar feeling of power but to a much much lesser degree.

But, in real life, without the gun in their hand, the cold hard truth might be that they are not actually so cool, powerful and almighty. In fact, they may be thought of by their classmates as losers.

Why do the people at school make them feel like losers when they are actually so cool and powerful??? A big question.